The study of the new plastic closure (and of the particular geometry of the neck of the associated vessel), which is wholly recyclable, has started from the analysis of the system nowadays on the market, called in particular “Cornelius keg”.
The Cornelius kegs of the IMI Cornelius Company have been and are uncontested market leaders.
The Cornelius kegs (also known as “soda kegs” or “pepsi kegs”) are a particular type of barrel used for dispensing soft drinks and draft beverages.
The main features of this barrel are:                its slim shape, which allows inserting many barrels inside a refrigerator;        its opening with wide mouth, which allows also manually performing the internal cleaning of the barrel;        its reduced capacity, about 18 liters (or 5 gallons) for the bigger ones and about 9 liters (or 3 gallons) for the smaller ones.        
Actually, these barrels are divided into two categories, according to the type of connection: “ball lock” (or Jolly) and “pin lock”.
The “Cornelius keg” has a very simple operation.
The keg head, which is made of steel/aluminium, is equipped with a main trap useful for the internal washing of the vessel, and with two connections (which can be, as stated above, “ball lock” or “pin lock”). One operates as entry for gas (where CO2 or nitrogen can be inserted) and the other one as outlet for liquid.
A dip tube is always connected (inside the vessel) to the liquid outlet, such tube collecting the liquid pushed by the pressure on the bottom, in order to enable completely emptying the keg.
This type of vessel however has various problems:                the Cornelius keg is re-usable and very costly and has no forgery-preventing systems which protect the beverage inside it;        the barrels are composed of many costly parts (some need a replacement after every use);        the Cornelius kegs can be re-filled, since their closures has no forgery-preventing systems, and therefore products (beverages) not certified by the manufacturers could sometimes be put on the market;        being re-usable, the vessel must necessarily go back, after their use, to the filling centre to be washed and sanitized;        the consumer must pay a high amount as caution of the vessel when he purchases the beverage in these kegs;        also for the manufacturer, the cost is high, because he will have to support expenses for transporting the filled vessel, but also for taking back the empty vessel to his company;        moreover, the management and washing costs are also born by the end user;        at “carbon footprint” and ecologic level, the Cornelius keg has a heavy impact on the environment, two to its transport (of a filled barrel and the return of the empty barrel) and washing (with great uses of water and disinfectant);        the Cornelius keg has several pieces which must necessarily be replaced at the end of every use (since the Cornelius keg, as previously stated, is re-usable, obviously after washing and sterilization);        the pieces which are normally exchanged upon every use are: CO2 pipe, internal valve, O-ring 8.4 Jolly, O-ring 8.4 pipe, red taps for handle, Jolly connections, safety valve, O-ring 8.4 cover. All these components have O-rings 8.4 and small springs inside them; the elastic and mechanical properties of these components, with their use, and with time, can worsen and thereby impair their pressure seal;        moreover, a normally used barrel has the gaskets used for the previously contained product, which therefore could modify the taste of the beverage inserted afterwards; an exchange of the O-rings 8.4 is compulsory to have always clean and efficient barrels. the Cornelius kegs, being re-usable, must necessarily go back to the filling centre, must be disassembled and sterilized, and moreover it is necessary to change all O-rings 8.4: therefore, high management costs will occur both for the filled barrel, and for the used “return” barrel; there is a single warranty seal (which is also a protection of the two connections from dirt and dust): it is a big-sized tap which covers the area of the two connections and is fastened with a warranty strap/seal only after its filling. Once having removed the tap (after its first use), if stored, it can be re-used by a possible counterfeiter (after he has filled again the keg with a different product), and again blocked with a new strap, certifying, with the same “regenerated” warranty seal with a new blocking strap, actually a non-original product;        since there are no recognition signs on the keg body, it is not easy, above all for the end user, to discriminate at first sight the gas connection from the liquid connection: many times the connections are reversed and therefore the system does not work and is blocked, thereby requiring the assistance intervention (additional costs).        